1 .\" (c) Copyright 1997-2009 by Matthew Dillon and Dima Ruban. Permission to
2 .\" use and distribute based on the DragonFly copyright. Supplied as-is,
3 .\" USE WITH EXTREME CAUTION.
10 .Nd mirror filesystems
14 .Op Fl v Ns Op Cm v Ns Op Cm v
36 .Oo Oo Ar user Ns Li @ Oc Ns Ar host : Oc Ns Ar source_dir
37 .Oo Oo Ar user Ns Li @ Oc Ns Ar host : Oc Ns Ar target_dir
41 utility makes an exact mirror copy of the source in the destination, creating
42 and deleting files and directories as necessary. UTimes, hardlinks,
43 softlinks, devices, permissions, and flags are mirrored. By default,
45 asks for confirmation if any file or directory needs to be removed from
46 the destination and does not copy files which it believes to have already
47 been synchronized (by observing that the source and destination files' sizes
50 does not cross mount points in either the source or the destination.
53 refuses to replace a destination directory with a file.
55 The following options are available:
58 If the source or target is a remote host, request that the
60 session be compressed.
64 .It Fl v Ns Op Cm v Ns Op Cm v
65 Set verboseness. By default
67 does not report its progress except when asking for confirmation. A single
69 will only report modifications made to the destination.
71 will report directories as they are being traversed as well as
72 modifications made to the destination.
74 will cause all files and directories to be reported whether or not
75 modifications are made.
77 Print directories as they are being traversed.
78 Useful to watch the progress;
79 this typically produces much less output than
82 Causes the output generated by
87 This can be useful for obtaining prompt progress updates through a pipe.
91 to print a summary at the end with performance counters.
93 Forces file updates to occur even if the files appear to be the same. If
96 option is used, this option will force a byte for byte comparison
97 between the original file and the file in the hardlink path, even if
98 all the stat info matches, but will still use a hardlink if they match.
104 Note the lack of a space.
106 Disable the disallow-file-replaces-directory safety feature. This
107 safety feature is enabled by default to prevent user mistakes from blowing
108 away everything accidentally.
110 Do not request confirmation when removing something.
112 Do not try to recreate CHR or BLK devices.
114 Line buffer verbose output.
118 Do not remove any files, just overwrite/add.
120 Generate and maintain a MD5 checkfile called
122 in each directory on the source
123 and do an MD5 check on each file of the destination when the destination
124 appears to be the same as the source. If the check fails,
125 the source is recopied to the destination. When you specify a destination
126 directory, the MD5 checkfile is only updated as needed and may not be updated
127 even if modifications are made to a source file. If you do not specify a
128 destination directory the
130 command forcefully regenerates the MD5 checkfile for every file in the source.
134 but allows you to specify the name of the MD5 checkfile.
137 will create a hardlink from a file found under
139 to the target instead of copying the source to the target if the file found
142 is identical to the source.
143 Note that a remote host specification should not be used for this option's
147 will be relative to the target machine.
149 This allows one to use
151 to create incremental backups of a filesystem. Create a direct
153 backup, and then specify the level 0 backup path with this option when
154 creating an incremental backup to a different target directory.
155 This method works so long as the filesystem does not hit a hardlink limit.
156 If the system does hit a hardlink limit,
158 will generate a warning and copy the file instead.
161 must record file paths for any hardlinked file while operating and therefore
162 uses a great deal more memory when dealing with hardlinks or hardlink-based
163 backups. Example use:
165 .Dl cpdup \-i0 \-s0 \-I \-H /backup/home.l0 /home /backup/home.l1
167 WARNING: If this option is used
169 must record the paths for all files it encounters while it operates
170 and it is possible that you may run the process out of memory.
172 The file found via the hardlink path will be byte-by-byte compared with the
177 option is also used, otherwise only the stat info is checked to determine
178 whether it matches the source.
180 This forces the contents of regular files to be verified, even if the
181 files appear to the be the same. Whereas the
183 (force) option forces a copy regardless, this option will avoid rewriting
184 the target if everything matches and the contents are verified to be the
187 This works the same as
189 but ignores mtime entirely, making it suitable for comparing HAMMER
190 master and slave filesystems or copies made without mtime retention.
194 into slave mode and is used to initiate the slave protocol on a remote
197 Generate and maintain a FSMID checkfile called
199 in each directory on the target.
201 will check the FSMID for each source file or directory against the checkfile
202 on the target and will not copy the file or recurse through the directory
203 when a match occurs. Any source file or directory with the same name as the
204 checkfile will be ignored. The FSMID will be re-checked after the copy
205 has been completed and
207 will loop on that directory or file until it is sure it has an exact copy.
209 Warning: FSMID is not always supported by a filesystem and may not be
210 synchronized if a crash occurs.
212 will simulate an FSMID when
213 it is otherwise not supported by the filesystem, and users should be aware
214 that simulated FSMIDs may change state in such cases even if the underlying
215 hierarchy does not due to cache flushes.
216 Additionally, the FSMID may not reflect changes made to remote filesystems
217 by other hosts. For example, using these options with NFS mounted sources
222 but allows you to specify the name of the FSMID checkfile.
226 to use the exclusion file
228 in each directory on the source to
229 determine which files to ignore. When this option is used, the exclusion
230 filename itself is automatically excluded from the copy. If this option is
231 not used then the filename
233 is not considered special and will
234 be copied along with everything else.
238 but allows you to specify the name of the exclusion file. This file is
239 automatically excluded from the copy. Only one exclusion file may be
244 can mirror directory structures across machines and can also do third-party
247 sessions are used and
249 is run on the remote machine(s) in slave mode.
252 option to pass additional flags to the ssh command if necessary.
254 The syntax of remote path specifications is similar to
256 In particular, that means that a local path containing a colon must
257 be preceded by a slash to prevent it being considered a remote host:
261 to look for a directory called
267 denotes the directory
269 on the local machine.
273 utility exits 0 if no error occurred and >0 if an error occurred.
283 command was originally created to update servers at BEST Internet circa 1997
284 and was placed under the
286 copyright for inclusion in the ports area in 1999.
287 The program was written by Matthew Dillon and Dima Ruban.
290 has a hardlink limit of 32767. Many programs, in particular CVS
291 with regards to its CVS/Root file, will generate a lot of hard links.
294 option it may not be possible for
296 to maintain these hard links. If this occurs,
298 will be forced to copy the file instead of link it, and thus not be able
299 to make a perfect copy of the filesystem.
301 Currently the remote protocol uses host byte order. Therefore,
303 cannot talk to machines that use a byte order
304 different from the local machine.
306 When so-called sparse files (i.e. files with "holes") are copied,
307 the holes will be filled in the target files, so they occupy
308 more physical disk space than the source files.